pete, let's go back to that picture we just saw from whdh up there, boston affiliate of nbc. what are the experts making of the fact that it was there, that bag, whatever it is sitting there before the explosion and then in this picture taken afterwards you can see the smoke trailing up to the left there diagonally? what does that tell us? >> it tells us it's something they're investigating, chris. they know, they believe very strongly that the bombs were brought to the scene in backpacks. but i think it's fair to say they're looking at whether after they got there, they put them in these shopping bags. now, that thing next to the -- to the bag that's just on the edge of the little spot shot circle there, that is a trash receptacle. could it be? it's a question. could it be the devices were placed in these trash bags next to trash receptacles to look inconspicuous? it's something that they're -- that they're studying and something that is a possibility. they don't know. but it's certainly an interesting lead. one of many they're looking at. >> well, again, i already pointed o